Overview
Eriosema squarrosum (Thunb.) Walp. is a plant species from the Fabaceae family, commonly known as the Harpoon Pea. It is native to southern Africa where it is found in a variety of habitats, including grasslands, savannas, and woodlands.
General Appearance
Eriosema squarrosum is a perennial herb, growing up to 1m tall with a woody rootstock. The leaves are alternate with three leaflets and are covered in fine hairs. The flowers, which vary in color from yellow to orange-red, grow in clusters of 2-5 along the stem. The fruit is a long, narrow pod that splits open when ripe to release the seeds.
Common Names
Eriosema squarrosum is commonly known as the Harpoon Pea due to the shape of the mature seed pods, which resemble harpoons. Other common names for the plant include the Mountain Eriosema, Oukiep-beans, and Klawerert.
Uses
Traditionally, Eriosema squarrosum has been used in Southern Africa for medicinal purposes. The roots and leaves are used to make a tea that is believed to have diuretic properties and can be used to treat coughs, colds, and fever. The plant's crushed leaves have also been used as a compress to treat inflammation and swelling. In modern times, the plant is often used in landscaping due to its attractive flowers and interesting seed pods.
Light Requirements
Eriosema squarrosum typically needs full sunlight to grow, and hence, it is commonly found in open areas. It is not a shade-tolerant plant and requires ample sunlight to thrive. Consequently, it flourishes well in areas with minimum shading, making it a fantastic plant for cultivation in sunny, open fields.
Temperature Requirements
Eriosema squarrosum can tolerate high temperatures, particularly during the growth and development seasons. This plant prefers warm climates with temperatures ranging between 25 to 30°C, considering it is native to the tropics. The growth rate decreases significantly at lower temperatures, and exposure to temperatures below 10°C can cause damage to the plant.
Soil Requirements
Eriosema squarrosum grows best in well-draining soils, particularly in sandy and loamy soils with a pH ranging from 6.0 to 7.5. Although it can tolerate slightly acidic or alkaline soils, the plant performs best in neutral soils. The soil should be moist but not water-logged, ensuring that the water drains adequately. Additionally, the plant requires soils with a good structure and nutrient content to prevent nutrient leaching and increase its adaptation to different soil environments.
Cultivation methods
Eriosema squarrosum (Thunb.) Walp. is a hardy plant that can grow in various soil types. It grows best in well-draining soils, and it is necessary to avoid waterlogging. The plant requires full sunlight and thrives in warm temperatures, with an optimal range of 25-30°C. Planting can be done in late spring, and it is best to use healthy seedlings. The plant's roots need adequate space to grow, so it is vital to leave enough spacing, about 20 to 25 cm apart.
Watering needs
Water is essential, especially during germination, when the soil should be kept moist without being soaked. Once the plant is established, it requires less water, and watering can be reduced to once every two or three weeks. During prolonged dry periods, regular watering is necessary to help the plant survive and thrive.
Fertilization
It is essential to provide the plant with adequate nutrients that are required for growth. A balanced fertilizer, such as 10-10-10, can be used during planting, and it should be sprinkled around the plant. The use of organic fertilizers is also recommended, as they provide a slow release of nutrients that the plant can use over a more extended period.
Pruning
Pruning should be done during the plant's dormant period to prevent damage to its active growth. Dead or broken limbs can be removed, and one should also remove any overgrown or weak stems. It is better to prune during autumn or early spring to help the plant to grow healthier and stronger.
Propagation of Eriosema squarrosum
Eriosema squarrosum is commonly known as the "South African living fossil" due to its remarkable ability to survive fire and drought. Propagating this plant requires careful consideration of its natural growing habitat and methods used for dispersal.
Seed Propagation
Eriosema squarrosum produces large numbers of seeds that are dispersed naturally by wind and water. Seed propagation is one of the most common ways to propagate E. squarrosum. Seeds can be germinated indoors in seed trays and transplanted once they have reached a manageable size, or sowed directly into the soil in the fall. To ensure good germination rates, it is recommended to scarify the seed coat by nicking or rubbing it slightly with sandpaper and soaking it in water for 24 hours before planting.
Vegetative Propagation
Vegetative propagation of E. squarrosum can be done via stem cuttings or layering. Stem cuttings can be taken from healthy, mature plants during the growing season and should consist of woody stem tips and two to three leaves. These cuttings should be dipped in rooting hormone and placed in sandy soil or perlite. Layering involves burying a portion of a stem in soil and allowing it to form its roots before detaching it from the parent plant.
Cultural Requirements
E. squarrosum is a hardy plant that thrives in hot, dry climates. It prefers well-draining soils and full sun exposure. When propagating this species, it is important to replicate these conditions to ensure successful germination and growth.
Disease Management
Eriosema squarrosum (Thunb.) Walp. is generally a hardy plant that is able to withstand many diseases. However, there are still a few common diseases that can affect it:
- Root rot: This disease is caused by various types of fungi, and it can result in wilting, yellowing leaves, and plant death. To prevent root rot, it is important to ensure proper drainage and not overwater the plant.
- Leaf spot: This disease is caused by fungi or bacteria and can cause brown or black spots on the leaves, which can eventually lead to leaf drop. To manage leaf spot, remove infected leaves and avoid overhead watering.
- Powdery mildew: This fungal disease appears as a white, powdery coating on the leaves. It can be managed by improving air circulation around the plant, removing infected leaves, and applying fungicides if necessary.
Pest Management
Eriosema squarrosum (Thunb.) Walp. can also be affected by a number of pests:
- Aphids: These small, soft-bodied insects can cause stunted growth, yellowing leaves, and distorted stems. They can be managed by spraying the plant with a strong stream of water, using insecticidal soap, or introducing natural predators like ladybugs or lacewings.
- Spider mites: These tiny pests can cause yellowing leaves and webbing on the plant. They can be managed by increasing humidity around the plant, wiping the leaves with a damp cloth, or using insecticidal soap.
- Caterpillars: These larvae of moths and butterflies can cause significant damage to the leaves and stems of the plant. To manage caterpillars, remove them by hand, use insecticidal sprays or dusts, or introduce natural predators like birds or parasitic wasps.
